feat: verify no netlify forms

Author: orinokai

src/build/content/prerendered.ts

@@ -18,6 +18,7 @@ import type {
   NetlifyIncrementalCacheValue,
 } from '../../shared/cache-types.cjs'
 import type { PluginContext } from '../plugin-context.js'
+import { verifyNoNetlifyForms } from '../verification.js'
 
 const tracer = wrapTracer(trace.getTracer('Next runtime'))
 
@@ -169,6 +170,11 @@ export const copyPrerenderedContent = async (ctx: PluginContext): Promise<void>
                   throw new Error(`Unrecognized content: ${route}`)
               }
 
+              // Netlify Forms are not support and require a workaround
+              if (value.kind === 'PAGE') {
+                verifyNoNetlifyForms(ctx, value.html)
+              }
+
               await writeCacheEntry(key, value, lastModified, ctx)
             }),
         ),

src/build/verification.ts

@@ -85,3 +85,11 @@ export async function verifyNoAdvancedAPIRoutes(ctx: PluginContext) {
     )
   }
 }
+
+export function verifyNoNetlifyForms(ctx: PluginContext, html: string) {
+  if (/<form[^>]*?\s(netlify|data-netlify)[=>\s]/.test(html)) {
+    ctx.failBuild(
+      `@netlify/plugin-next@5 does not support Netlify Forms. Refer to https://ntl.fyi/next-runtime-forms-migration for migration example.`,
+    )
+  }
+}